Campaigners against oil exploration at Leith Hill have vowed to highlight to the Environment Agency (EA) water company warnings about the risk of contamination to public water supplies should the plans go ahead, which could affect up to 180,000 people in Surrey.

A public meeting will be held at the John Venus Hall, in Coldharbour, on Wednesday (November 25) to discuss groundwater protection, with the Leith Hill Action Group (LHAG) expected to urge the EA to look again at objections from Sutton and East Surrey Water (SESW) to proposed drilling site in the Surrey Hills Area of Outstanding Natural beauty.

"To be successful they must prove to the agency that they will not contaminate the environment or the water supply for central Surrey.”

A senior SESW director has claimed the drilling could potentially contaminate up to 180,000 Surrey consumers water supply. Europa has dismissed these claims as "scaremongering".

'Increased risk'

Lester Sonden, wholesale services director of SESW, said he is concerned about the potential for long-term contamination of water sources.

He said: “Our objection to drilling in this location is that it will increase the risk of polluting the aquifer of the local watercourse that is used for public water supply.

“Besides the risk of contaminating our borehole sources at Dorking, there is also a risk that contamination could lead to pollution of the River Mole, which in turn could affect our sources at Leatherhead.

“This is because our water sources are connected, albeit sometimes indirectly.

“We are concerned that in the event of a leak or a spill, the proposed mitigation measures will not guarantee the protection of our aquifers.

“As a water company responsible for the public water supply, it is incumbent upon us to bring this increased risk to people’s attention.”

Children from St Joseph's RC Primary School in Dorking have got behind the Love Leith Hill campaign (Image: Beth Duffell)

Mr Sonden said that should groundwater sources at Dorking or Leatherhead be contaminated, along with the water at the water company’s treatment works, around 70,000 properties could be affected in Dorking, Leatherhead, Fetcham, Ashtead, Oxshott and Cobham.

“The EA has required additional protection against the risk in the short term," he said.

"But longer term the risks are not so well understood. However well-designed, there is a risk of failure at some time in the future.

"Such contamination, however small, could be quite long-lived if it is not spotted.”

Mr Sonden aired these concerns at two public inquiries into the initial Bury Hill Wood planning application that was finally approved in August.

At the time, the EA gave assurances that separate environmental permits would deal with any risks to water supplies and that monitoring of the site would take place.

'Scaremongering'

Referring to the environmental evidence given at the second public enquiry by the EA’s and Europa’s experts, Hugh MacKay, the oil and gas company’s chief executive, said: “Europa is concerned that SESW appears to be ignoring the technical evidence presented at the inquiry, the planning inspector’s decision and the role of the EA.

“For SESW to come back now and suggest 180,000 homes are at risk is simply scaremongering.

“As considered carefully in the inquiry, there is no technical hydrogeological evidence to support this statement and SESW was not sufficiently concerned at the time to engage its own expert at the inquiry.”

A spokesman for the EA said if the permit is issued, it will require Europa to carry out monitoring at the site and immediately around the site.

“This requirement will continue until the environmental permit is surrendered, which will be after the period of drilling, when the EA is satisfied,” said the spokesman.

“The objectives from the outset will be to ensure that the proposal minimises the risk of impact and does not have a cause contamination of the groundwater environment in the short term or the longer term.”